In a conventional network, each router maintains a graph representing the router's network. A router in a data center may, for example, maintain a graph depicting all nodes and links in the data center and possibly some nodes outside the data center. A router's software uses the graph to calculate the shortest paths to network destinations and to maintain a forwarding table identifying router interfaces for packets addressed to the network destinations. A typical router also generates and sends control packets to notify other routers to of updated link states and thereby allow the other routers to update their graphs when link states change.